Geophysical investigation of Karkarku earthdam embankment.

Olorunfemi, M. O.; Ojo, John Sunday; Sonuga, F A; Ajayi, O. O.; Oladapo, Michael Ilesanmi

doi:10.4314/gjpas.v6i1.16087

Cited by 9 publications

(6 citation statements)

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“…The integrity of a dam embankment can be undermined by the existence of geological features (e.g. faults, fractures, fissures, jointed or shear zones) precipitated seepage zones in the bedrock and/or discontinuities in the structure itself [3]. Earth dams in their natural state experience some degree of seepage and spillage flow from the reservoir and through permeable soils.…”

Section: Introductionmentioning

confidence: 99%

“…Earth dams in their natural state experience some degree of seepage and spillage flow from the reservoir and through permeable soils. Age of the dam, poor construction material; defect in the design can also responsible for dam collapse [3]. All the factors may cause the physical properties of the materials in the dam to change.…”

Section: Introductionmentioning

confidence: 99%

“…The use of electrical resistivity methods is gaining popularity among the geophysicists for post-construction deformation checks of seepage from drains in and around large dams is important to anticipate and permits remedial action to be taken before structural failure occurs. The methods are not only environmentally friendly and inexpensive but also timely [3][4][5][6][7][8][9][10][11][12][13]. As a result, the electrical resistivity survey involving the vertical electrical sounding (VES) using the Schlumberger array and 2-D electrical resistivity imaging using the dipole-dipole array was used along the crest of the of Oba earth dam, Ogbomoso Southwestern Nigeria to check the integrity.…”

Section: Introductionmentioning

confidence: 99%

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Geophysical Investigation of Oba Earth-Fill Dam Embankment using Electrical Resistivity Method

Bayowa¹,

Ogungbesan²,

Mudashir³

2019

Int J Earth Sci Geophys

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Continual post-construction checks on dam embankment are inevitable to forestall the possible catastrophes associated with its structural failure. In view of this, electrical resistivity (ER) surveys involving vertical electrical sounding (VES) and dipole-dipole profiling were conducted along the Oba dam embankment as a part of routine deformation monitoring for any possible seepage(s) around the dam embankment. Thirty-one vertical electrical soundings and thirty-five dipole-dipole horizontal profiling data were carried out on a 350 m long (west-east trending) traverse established along dam embankment. The iterated VES curves were mainly KH-type suggesting that Oba dam embankment is underlain by four geoelectric layers; topsoil (caprock), fill (granite materials), core (plastic-clay/wet clay) and basement bedrock with resistivity values range of between 53-249 Ωm, 205-1084 Ωm, 15-124 Ωm and 281-1375 Ωm, respectively. The dipole-dipole 2-D resistivity structure along the dam embankment showed no evidence of structural distress/weakness within the underlying sequences. Therefore, by integrating results obtained from geoelectric section and 2D resistivity structure based on the layer resistivity/ lithological composition of the core materials (15-124 Ωm/plastic clay/clay/sandy clay), Oba earth-fill dam embankment integrity was good to very good indicating no seepage zone(s).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Geophysical Investigation of Oba Earth-Fill Dam Embankment using Electrical Resistivity Method

Bayowa¹,

Ogungbesan²,

Mudashir³

2019

Int J Earth Sci Geophys

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“…Although the importance of the geophysical method in engineering geophysics exploration work has not been proved, it has also been considered that another method of geoscience exploration approach can serve as a supplement to gather information on the condition of pavement depth and layer thickness, especially for a long continuous pavement assessment, thus reducing the number of coring tests that can cause damage to the pavement structure. A typical example is the combination of the geophysical and geotechnical approach to engineering problems [9,10,11].…”

Section: Geoscience Engineeringmentioning

confidence: 99%

Non-Invasive Geophysical Investigation of Failure Along a Section of Ago-Iwoye Market Road, Ago-Iwoye, Southwestern Nigeria

ODUGBESAN

Mosuro

Dada

et al. 2023

GSE

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A detailed geophysical investigation was carried out to determine if the subsurface geology is responsible for the failures along this road section. This study aims to image and identify competent, moderately competent, and incompetent zones of the subsurface soil and thus to find out if geology is responsible for the failure along this section of the road. Electrical Resistivity Imaging (ERI) using the Wenner array 2D Imaging, and Vertical Electrical Sounding (VES) using the Schlumberger array were adopted for this survey. The geoelectric section from the VES revealed the presence of 3 lithological layers; topsoil, weathered layer (clay, sandy clay, clayey sand), and basement, which is also true for the electrical resistivity images revealed by the 2D electrical resistivity imaging. The results showed that the shallow subsurface beneath the road section is mostly underlain with clay that is geotechnically incompetent and not suitable for construction. The causes of road failure are believed to be the result of the incompetent clayey topsoil and the weathered layer seen in the profiles, which expand when absorbing water and shrink when drying, thus causing instability beneath the pavement due to the low shear strength and high compressibility, and also due to fractured basement rocks at shallow depths.

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“…The location of such features are often subjected to spatial error while the geometry and characteristics usually require further investigation. The present study investigated the characteristics (lateral extent, width, depth extent and orientation) of the suspected structural feature in order to provide information for government and other stake holders interested in future groundwater and/or engineering infrastructural development within the study area (e.g., Olorunfemi et al, 2000;Sangodiji and Olorunfemi, 2013;Fatoba et al, 2015 andFatoba et al, 2018). The outcome of the study can also be an update on the structural disposition of the existing Ogbomoso Sheet 222 geological map.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and Resistivity Imaging of a probable Fault within the Precambrian Crystalline Rocks in Ogbomoso, Southwestern Nigeria

Bayowa

Fawole

Olorunfemi

et al. 2023

Preprint

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A linear geological structure which is suspected to be a fault within the Precambrian Basement Complex rocks of Ogbomoso, Southwestern Nigeria is found in the geological map of Ogbomoso Southwest Sheet 222. The ground magnetic and electrical resistivity methods were used to investigate the structure and determine its physical characteristics. Five (5) traverses with lengths varying from 700–800 m and trending NNW-SSE (N338oW) were established perpendicularly (ENE-WSW, N68oE) to the suspected fault. Total magnetic field data were acquired at 10 m interval, corrected for diurnal variation and inverted using the Geosoft Oasis Montaj software package. Dipole-Dipole resistivity data were acquired on the traverses using a dipole length of 20 m with expansion factor n varying from 1 to 5 and modelled to generate 2D resistivity structures with the DIPPRO™ software package. Thirty-seven (37) depth sounding data were acquired, quantitatively interpreted and the results used to generate geoelectric sections along the suspected geologic features. Three (3) parallel linear features F1-F1, F2-F2 and F3-F3 characterized by peak negative (-110 to -20 nT) magnetic anomalies typical of thin and thick dykes (in low magnetic latitude) and low resistivity vertical discontinuities (˃ 188 m deep, 30–153 m wide) within 2D resistivity structures, were identified across the five traverses. F1-F1 coincided with the suspected fault, F1-F1. F2-F2 and F3-F3 are parallel and suspected to be syngenetic with F1-F1. The absence of a significant vertical displacement, typical of normal faulting, in the basement bedrock on the 2D geoelectric sections corroborated the inference of strike slip faulting from the geological map.

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Geophysical investigation of Karkarku earthdam embankment.

Cited by 9 publications

References 0 publications

Geophysical Investigation of Oba Earth-Fill Dam Embankment using Electrical Resistivity Method

Geophysical Investigation of Oba Earth-Fill Dam Embankment using Electrical Resistivity Method

Non-Invasive Geophysical Investigation of Failure Along a Section of Ago-Iwoye Market Road, Ago-Iwoye, Southwestern Nigeria

Magnetic and Resistivity Imaging of a probable Fault within the Precambrian Crystalline Rocks in Ogbomoso, Southwestern Nigeria

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